6Lo Working Group Y-G. Hong
Internet-Draft Y-H. Choi
Intended status: Standards Track ETRI
Expires: April 19, 2016 J-S. Youn
DONG-EUI Univ
D-K. Kim
KNU
J-H. Choi
Samsung Electronics Co.,
October 17, 2015
Transmission of IPv6 Packets over Near Field Communicationdraft-ietf-6lo-nfc-02
Abstract
Near field communication (NFC) is a set of standards for smartphones
and portable devices to establish radio communication with each other
by touching them together or bringing them into proximity, usually no
more than 10 cm. NFC standards cover communications protocols and
data exchange formats, and are based on existing radio-frequency
identification (RFID) standards including ISO/IEC 14443 and FeliCa.
The standards include ISO/IEC 18092 and those defined by the NFC
Forum. The NFC technology has been widely implemented and available
in mobile phones, laptop computers, and many other devices. This
document describes how IPv6 is transmitted over NFC using 6LowPAN
techniques.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 19, 2016.
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Internet-Draft IPv6 over NFC October 20151. Introduction
NFC is a set of short-range wireless technologies, typically
requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on
ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to
424 kbit/s. NFC always involves an initiator and a target; the
initiator actively generates an RF field that can power a passive
target. This enables NFC targets to take very simple form factors
such as tags, stickers, key fobs, or cards that do not require
batteries. NFC peer-to-peer communication is possible, provided both
devices are powered. NFC builds upon RFID systems by allowing two-
way communication between endpoints, where earlier systems such as
contactless smart cards were one-way only. It has been used in
devices such as mobile phones, running Android operating system,
named with a feature called "Android Beam". In addition, it is
expected for the other mobile phones, running the other operating
systems (e.g., iOS, etc.) to be equipped with NFC technology in the
near future.
Considering the potential for exponential growth in the number of
heterogeneous air interface technologies, NFC would be widely used as
one of the other air interface technologies, such as Bluetooth Low
Energy (BT-LE), Wi-Fi, and so on. Each of the heterogeneous air
interface technologies has its own characteristics, which cannot be
covered by the other technologies, so various kinds of air interface
technologies would be existing together. Therefore, it is required
for them to communicate each other. NFC also has the strongest point
(e.g., secure communication distance of 10 cm) to prevent the third
party from attacking privacy.
When the number of devices and things having different air interface
technologies communicate each other, IPv6 is an ideal internet
protocols owing to its large address space. Also, NFC would be one
of the endpoints using IPv6. Therefore, This document describes how
IPv6 is transmitted over NFC using 6LoWPAN techiques with following
scopes.
o Overview of NFC technologies;
o Specifications for IPv6 over NFC;
* Neighbor Discovery;
* Addressing and Configuration;
* Header Compression;
* Fragmentation & Reassembly for a IPv6 datagram;
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Internet-Draft IPv6 over NFC October 2015RFC4944 [1] specifies the transmission of IPv6 over IEEE 802.15.4.
The NFC link also has similar characteristics to that of IEEE
802.15.4. Many of the mechanisms defined in the RFC4944 [1] can be
applied to the transmission of IPv6 on NFC links. This document
specifies the details of IPv6 transmission over NFC links.
2. Conventions and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [2].
3. Overview of Near Field Communication Technology
NFC technology enables simple and safe two-way interactions between
electronic devices, allowing consumers to perform contactless
transactions, access digital content, and connect electronic devices
with a single touch. NFC complements many popular consumer level
wireless technologies, by utilizing the key elements in existing
standards for contactless card technology (ISO/IEC 14443 A&B and
JIS-X 6319-4). NFC can be compatible with existing contactless card
infrastructure and it enables a consumer to utilize one device across
different systems.
Extending the capability of contactless card technology, NFC also
enables devices to share information at a distance that is less than
10 cm with a maximum communication speed of 424 kbps. Users can
share business cards, make transactions, access information from a
smart poster or provide credentials for access control systems with a
simple touch.
NFC's bidirectional communication ability is ideal for establishing
connections with other technologies by the simplicity of touch. In
addition to the easy connection and quick transactions, simple data
sharing is also available.
3.1. Peer-to-peer Mode of NFC
NFC-enabled devices are unique in that they can support three modes
of operation: card emulation, peer-to-peer, and reader/writer. Peer-
to-peer mode enables two NFC-enabled devices to communicate with each
other to exchange information and share files, so that users of NFC-
enabled devices can quickly share contact information and other files
with a touch. Therefore, a NFC-enabled device can securely send IPv6
packets to any corresponding node on the Internet when a NFC-enabled
gateway is linked to the Internet.
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Internet-Draft IPv6 over NFC October 2015
Transport. The Link Management component is responsible for
serializing all connection-oriented and connectionless LLC PDU
(Protocol Data Unit) exchanges and for aggregation and disaggregation
of small PDUs. This component also guarantees asynchronous balanced
mode communication and provides link status supervision by performing
the symmetry procedure. The Connection-oriented Transport component
is responsible for maintaining all connection-oriented data exchanges
including connection set-up and termination. The Connectionless
Transport component is responsible for handling unacknowledged data
exchanges.
3.3. NFC-enabled Device Addressing
NFC-enabled devices are identified by 6-bit LLC address. In other
words, Any address SHALL be usable as both an SSAP and a DSAP
address. According to NFCForum-TS-LLCP_1.1 [3], address values
between 0 and 31 (00h - 1Fh) SHALL be reserved for well-known service
access points for Service Discovery Protocol (SDP). Address values
between 32 and 63 (20h - 3Fh) inclusively, SHALL be assigned by the
local LLC as the result of an upper layer service request.
3.4. NFC MAC PDU Size and MTU
As mentioned in Section 3.2, an IPv6 packet SHALL be received at LLCP
of NFC and transported to an Unnumbered Information Protocol Data
Unit (UI PDU) and an Information Field in Protocol Data Unit (I PDU)
of LLCP of the NFC-enabled peer device. The format of the UI PDU and
I PDU SHALL be as shown in Figure 2 and Figure 3.
0 0 1 1
0 6 0 6
+------+----+------+-------------------------------------------+
|DDDDDD|1100|SSSSSS| Service Data Unit |
+------+----+------+-------------------------------------------+
| <-- 2 bytes ---> | |
| <------------------- 128 ~ 2176 bytes ---------------------> |
| |
Figure 2: Format of the UI PDU in NFC
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0 0 1 1 2 2
0 6 0 6 0 4
+------+----+------+----+----+---------------------------------+
|DDDDDD|1100|SSSSSS|N(S)|N(R)| Service Data Unit |
+------+----+------+----+----+---------------------------------+
| <------- 3 bytes --------> | |
| <------------------- 128 ~ 2176 bytes ---------------------> |
| |
Figure 3: Format of the I PDU in NFC
The I PDU sequence field SHALL contain two sequence numbers: The send
sequence number N(S) and the receive sequence number N(R). The send
sequence number N(S) SHALL indicate the sequence number associated
with this I PDU. The receive sequence number N(R) value SHALL
indicate that I PDUs numbered up through N(R) - 1 have been received
correctly by the sender of this I PDU and successfully passed to the
senders SAP identified in the SSAP field. These I PDUs SHALL be
considered as acknowledged.
The information field of an I PDU SHALL contain a single service data
unit. The maximum number of octets in the information field SHALL be
determined by the Maximum Information Unit (MIU) for the data link
connection. The default value of the MIU for I PDUs SHALL be 128
octets. The local and remote LLCs each establish and maintain
distinct MIU values for each data link connection endpoint. Also, An
LLC MAY announce a larger MIU for a data link connection by
transmitting an MIUX extension parameter within the information
field. If no MIUX parameter is transmitted, the default MIU value of
128 SHALL be used. Otherwise, the MTU size in NFC LLCP SHALL
calculate the MIU value as follows:
MIU = 128 + MIUX.
According to NFCForum-TS-LLCP_1.1 [3], format of the MIUX parameter
TLV is as shown in Figure 4.
0 0 1 2 3
0 8 6 2 1
+--------+--------+----------------+
| Type | Length | Value |
+--------+--------+----+-----------+
|00000010|00000010|1011| MIUX |
+--------+--------+----+-----------+
| <-------> |
0x000 ~ 0x7FF
Figure 4: Format of the MIUX Parameter TLV
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When the MIUX parameter is encoded as a TLV, the TLV Type field SHALL
be 0x02 and the TLV Length field SHALL be 0x02. The MIUX parameter
SHALL be encoded into the least significant 11 bits of the TLV Value
field. The unused bits in the TLV Value field SHALL be set to zero
by the sender and SHALL be ignored by the receiver. However, a
maximun value of the TLV Value field can be 0x7FF, and a maximum size
of the MTU in NFC LLCP SHALL calculate 2176 bytes.
4. Specification of IPv6 over NFC
NFC technology sets also has considerations and requirements owing to
low power consumption and allowed protocol overhead. 6LoWPAN
standards RFC4944 [1], RFC6775 [4], and RFC6282 [5] provide useful
functionality for reducing overhead which can be applied to BT-LE.
This functionality comprises of link-local IPv6 addresses and
stateless IPv6 address auto-configuration (see Section 4.3), Neighbor
Discovery (see Section 4.5) and header compression (see Section 4.7).
One of the differences between IEEE 802.15.4 and NFC is that the
former supports both star and mesh topology (and requires a routing
protocol), whereas NFC can support direct peer-to-peer connection and
simple mesh-like topology depending on NFC application scenarios
because of very short RF distance of 10 cm or less.
4.1. Protocol Stacks
Figure 5 illustrates IPv6 over NFC. Upper layer protocols can be
transport protocols (TCP and UDP), application layer, and the others
capable running on the top of IPv6.
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Internet-Draft IPv6 over NFC October 20154.3. Stateless Address Autoconfiguration
A NFC-enabled device (i.e., 6LN) performs stateless address
autoconfiguration as per RFC4862 [6]. A 64-bit Interface identifier
(IID) for a NFC interface MAY be formed by utilizing the 6-bit NFC
LLCP address (i.e., SSAP or DSAP) (see Section 3.3). In the
viewpoint of address configuration, such an IID MAY guarantee a
stable IPv6 address because each data link connection is uniquely
identified by the pair of DSAP and SSAP included in the header of
each LLC PDU in NFC.
Following the guidance of RFC7136 [10], interface Identifiers of all
unicast addresses for NFC-enabled devices are formed on the basis of
64 bits long and constructed in a modified EUI-64 format as shown in
Figure 6.
0 1 3 4 5 6
0 6 2 8 8 3
+----------------+----------------+----------------+----------+------+
|0000000000000000|0000000011111111|1111111000000000|0000000000| SSAP |
+----------------+----------------+----------------+----------+------+
Figure 6: Formation of IID from NFC-enabled device adddress
In addition, the "Universal/Local" bit in the case of NFC-enabled
device address MUST be set to 0 RFC4291 [7].
4.4. IPv6 Link Local Address
Only if the NFC-enabled device address is known to be a public
address the "Universal/Local" bit can be set to 1. The IPv6 link-
local address for a NFC-enabled device is formed by appending the
IID, to the prefix FE80::/64, as depicted in Figure 7.
0 0 0 1
0 1 6 2
0 0 4 7
+----------+------------------+----------------------------+
|1111111010| zeros | Interface Identifier |
+----------+------------------+----------------------------+
| |
| <---------------------- 128 bits ----------------------> |
| |
Figure 7: IPv6 link-local address in NFC
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The tool for a 6LBR to obtain an IPv6 prefix for numbering the NFC
network is can be accomplished via DHCPv6 Prefix Delegation (RFC3633
[8]).
4.5. Neighbor Discovery
Neighbor Discovery Optimization for 6LoWPANs (RFC6775 [4]) describes
the neighbor discovery approach in several 6LoWPAN topologies, such
as mesh topology. NFC does not consider complicated mesh topology
but simple multi-hop network topology or directly connected peer-to-
peer network. Therefore, the following aspects of RFC6775 are
applicable to NFC:
1. In a case that a NFC-enabled device (6LN) is directly connected
to 6LBR, A NFC 6LN MUST register its address with the 6LBR by
sending a Neighbor Solicitation (NS) message with the Address
Registration Option (ARO) and process the Neighbor Advertisement
(NA) accordingly. In addition, DHCPv6 is used to assigned an
address, Duplicate Address Detection (DAD) is not required.
2. For sending Router Solicitations and processing Router
Advertisements the NFC 6LNs MUST follow Sections 5.3 and 5.4 of
the RFC6775.
4.6. Dispatch Header
All IPv6-over-NFC encapsulated datagrams transmitted over NFC are
prefixed by an encapsulation header stack consisting of a Dispatch
value followed by zero or more header fields. The only sequence
currently defined for IPv6-over-NFC is the LOWPAN_IPHC header
followed by payload, as depicted in Figure 8.
+---------------+---------------+--------------+
| IPHC Dispatch | IPHC Header | Payload |
+---------------+---------------+--------------+
Figure 8: A IPv6-over-NFC Encapsulated 6LOWPAN_IPHC Compressed IPv6
Datagram
The dispatch value may be treated as an unstructured namespace. Only
a single pattern is used to represent current LoBAC functionality.
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+------------+--------------------+-----------+
| Pattern | Header Type | Reference |
+------------+--------------------+-----------+
| 01 1xxxxx | 6LOWPAN_IPHC | [RFC6282] |
+------------+--------------------+-----------+
Figure 9: Dispatch Values
Other IANA-assigned 6LoWPAN Dispatch values do not apply to this
specification.
4.7. Header Compression
Header compression as defined in RFC6282 [5] , which specifies the
compression format for IPv6 datagrams on top of IEEE 802.15.4, is
REQUIRED in this document as the basis for IPv6 header compression on
top of NFC. All headers MUST be compressed according to RFC6282
encoding formats.
Therefore, IPv6 header compression in RFC6282 [5] MUST be
implemented. Further, implementations MAY also support Generic
Header Compression (GHC) of RFC7400 [11]. A node implementing GHC
MUST probe its peers for GHC support before applying GHC.
If a 16-bit address is required as a short address of IEEE 802.15.4,
it MUST be formed by padding the 6-bit NFC link-layer (node) address
to the left with zeros as shown in Figure 10.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding(all zeros)| NFC Addr. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: NFC short adress format
4.8. Fragmentation and Reassembly
NFC provides fragmentation and reassembly (FAR) for payloads from 128
bytes up to 2176 bytes as mention in Section 3.4. The MTU of a
general IPv6 packet can fit into a sigle NFC link frame. Therefore,
the FAR functionality as defined in RFC4944, which specifies the
fragmentation methods for IPv6 datagrams on top of IEEE 802.15.4, is
NOT REQUIRED in this document as the basis for IPv6 datagram FAR on
top of NFC. The NFC link connection for IPv6 over NFC MUST be
configured with an equivalent MIU size to fit the MTU of IPv6 Packet.
However, the default configuration of MIUX value is 0x480 in order to
fit the MTU (1280 bytes) of a IPv6 packet.
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on the left with a zero. In addition, the NFC Destination Address,
0x3F, MUST not be used as a unicast NFC address of SSAP or DSAP.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding(all zeros)|1 1 1 1 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Multicast address mapping
5. Internet Connectivity Scenarios
As two typical scenarios, the NFC network can be isolated and
connected to the Internet.
5.1. NFC-enabled Device Connected to the Internet
One of the key applications by using adaptation technology of IPv6
over NFC is the most securely transmitting IPv6 packets because RF
distance between 6LN and 6LBR SHOULD be within 10 cm. If any third
party wants to hack into the RF between them, it MUST come to nearly
touch them. Applications can choose which kinds of air interfaces
(e.g., BT-LE, Wi-Fi, NFC, etc.) to send data depending
characteristics of data. NFC SHALL be the best solution for secured
and private information.
Figure 13 illustrates an example of NFC-enabled device network
connected to the Internet. Distance between 6LN and 6LBR SHOULD be
10 cm or less. If there is any of close laptop computers to a user,
it SHALL becomes the 6LBR. Additionally, When the user mounts a NFC-
enabled air interface adapter (e.g., portable small NFC dongle) on
the close laptop PC, the user's NFC-enabled device (6LN) can
communicate the laptop PC (6LBR) within 10 cm distance.
************
6LN ------------------- 6LBR -----* Internet *------- CN
| (dis. 10 cm or less) | ************ |
| | |
| <-------- NFC -------> | <----- IPv6 packet ------> |
| (IPv6 over NFC packet) | |
Figure 13: NFC-enabled device network connected to the Internet
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Internet-Draft IPv6 over NFC October 20155.2. Isolated NFC-enabled Device Network
In some scenarios, the NFC-enabled device network may transiently be
a simple isolated network as shown in the Figure 14.
6LN ---------------------- 6LR ---------------------- 6LN
| (10 cm or less) | (10 cm or less) |
| | |
| <--------- NFC --------> | <--------- NFC --------> |
| (IPv6 over NFC packet) | (IPv6 over NFC packet) |
Figure 14: Isolated NFC-enabled device network
In mobile phone markets, applications are designed and made by user
developers. They may image interesting applications, where three or
more mobile phones touch or attach each other to accomplish
outstanding performance. For instance, three or more mobile phones
can play multi-channel sound of music together. In addition,
attached three or more mobile phones can make an extended banner to
show longer sentences in a concert hall.
6. IANA Considerations
There are no IANA considerations related to this document.
7. Security Considerations
The method of deriving Interface Identifiers from 6-bit NFC Link
layer addresses is intended to preserve global uniqueness when it is
possible. Therefore, it is to required to protect from duplication
through accident or forgery.
8. Acknowledgements
We are grateful to the members of the IETF 6lo working group.
Michael Richardson, Suresh Krishnan, Pascal Thubert, Carsten Bormann,
and Alexandru Petrescu have provided valuable feedback for this
draft.
9. References9.1. Normative References
[1] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<http://www.rfc-editor.org/info/rfc4944>.
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